Lighting device



g- 1955 w. DUBRO'FF ET AL LIGHTING DEVICE Filed Feb. 10, 1954 FiGZ INVENTORS. WARREN DUBROFF MALKAN A. PEARLMAN ATTORNEY United States Patent LIGHTING DEVICE Warren Du Broil, Highland Park, and Malkan A. Pearlmau, Chicago, Ill.

Application February 10, 1954, Serial No. 409,488

3 Claims. (Cl. 315-282) This invention relates in general to lighting devices or fixtures and more particularly to a device primarily for household, domestic, commercial and industrial use capable of having its illuminating intensity varied thru an infinite range of values from zero to the maximum rating of the incandescent lamp or lamps which are employed in the device.

The provision of a lighting device of the character referred to above constitutes the principal object of this invention.

Lighting devices better known as floor and table lamps are in common use today and have been for some time. Also voltage controlling devices such as variable autotransformers are well known. However the incorporation of a voltage regulating device in a lamp in such manner as to constitute a completely self-contained integral intensity controlling lighting device where the operating means is external and yet arranged to aiford manual adjustment of the illuminating intensity is another object of this invention.

Another object of this invention is to incorporate into the body portion of such a device for illuminating purposes a voltage dividing unit which although infinitely variable thru a range of voltages from zero to the line voltage supplying the incandescent lamps or lamp is subject to substantially no heat losses notwithstanding extended operation.

In keeping with the last mentioned object, it is another object of this invention to incorporate an auto'transformer in a particular manner into the body portion of an illuminating device.

Still another object of this invention is to provide a voltage dividing unit incorporated within the body portion of an illuminating device with an operating means extending thru the body of the device and terminating externally thereof in an element for external manipulation and which forms an integral part of the external design of the device.

Yet another object of this invention is to provide in an illuminating device combination as set forth in the foregoing objects, a circuit breaking switch by means of which the lamp or bulb may be completely cut out of the operating circuit when the illuminating intensity has been reduced below the visual range.

Still another object of this invention is to incorporate the voltage dividing unit mentioned into the base portion of the body of the device thereby effecting a low and stable center of gravity in the device so that it will be less subject to being accidentally upset or overturned.

These objects and additional advantages and features will appear more fully hereinafter as the following description proceeds taken in conjunction with the accompanying sheet of drawings wherein:

Fig. 1 is an elevational view of an illuminating device incorporating the present invention.

Fig. 2 is an elevational view of the device of Figure 1 taken at ninety degrees therefrom with a portion cut away to reveal the internal parts.

I a/tented Aug. 9, 1955 "ice Fig. 3 is a schematic view of the circuit arrangement 2 for the device illustrated in Figures 1 and 2 and incorporating the circuit breaking switch feature.

Fig. 4 is a schematic view of another circuit similar to that shown in Figure 3 but with the switch arrangement 7 omitted.

or to the bulb by any suitable or conventional means.

- To this extent the device 11 may be of any type, for example either of the table, wall or floor lamp variety, and of any external shape and design compatible with the es sential elements of the invention, and for either household, residential, commercial or industrial applications.

Within the lamp body 12 and preferably within the lower or base portion 13 thereof, there is mounted as by a bracket 16, a voltage dividing or regulating unit 17 of the type which is substantially subject to no heat losses or dissipation despite continued operation over protracted periods of time, and which can be toroidal or rectangular in form. Such a voltage dividing unit is best embodied in an autotransformer chosen for a maximum wattage rating most particularly suited for the amount of maximum illumination to be delivered by the lamp.

spectively. Obviously units of greater wattage ratings may be employed if incandescent lamps of greater maximum wattage are to be employed, but for all practical purposes the rating indicated should be adequate for any usual use. The toroidal Winding 18, core 19, voltage selecting arm 20, brush 21 and rotatable operating shaft 22 to which the voltage selecting arm is nonrotatably attached are all conventional components of a commercially available autotransformer and require no further explanation herein. The bracket 16 is so arranged that the operating shaft 22 of the autotransformer l7 extends thru a suitable aperture 23 in the lamp body 12 and is terminated externally thereof by an operating element or knob 24 also non-rotatably affixed to the shaft 22. The operating element or knob 24 may be of any selected shape or size convenient for manual manipulation and preferably is designed to complement and form an integral part of the external design of the particular device involved. The lighting device may further be provided if desired with a circuit breaking switch 25 which if utilized may preferably comprise a commercially available miniature switch having a pair of normally closed contacts 26 and 27 connected into one side of a line from a suitable source or main V of A. C. electric current. As illustrated in Figure 3, the switch 25 is preferably and as is conventional practice placed in the so called hot side 29 of the line ahead of the autotransformer. The other or ground side of the line is designated at 28. Contacts 26 and 27 of the switch 25 are operated thru a plunger 30 (Fig. 2) depressed at a given position of rotation of the shaft 22 of the autotransformer by a suitable cam 31 non-rotatably mounted on said shaft. For convenience of illustration, the plunger 20 is schematically illustrated in Figure 3 as being operated by a buffer member 21 on the shaft 22.

As readily seen in the circuit diagram of Figure 3, the high and low voltage ends of the toroidal coil 18 of the autotransformer 17 indicated H and L are connected across the impressed voltage V, that is with one end to line 28 and the other end to line 29. The incandescent lamp 15 is connected on one side to line 28 and on the other side to the voltage selecting arm 20 of the autotransformer 17.

Assuming that the illuminating device 11 is not in us and viewing the circuit of Figure 4, the selecting arm 20 will be on point L of the coil 18 at which point no voltage exists across the bulb 15. The bulb 15 will be extinguished therefore but the coil 18 remains energized and a small amount of current for magnetization will continue to be consumed. Autotransformer design being such as it is, this will not be great so that no appreciable heat is dissipated. Nevertheless it is preferred as illustrated in Figure 3 to provide a circuit breaker switch 25 having normally closed contacts 26 and 27 in the lines from the voltage source V. When the voltage selecting arm 20 is on point L of the coil 18, the cam 31 will depress the switch arm 30 to open the contacts 26 and 27 thereby breaking the circuit completely and deenergizing the transformer as well.

At any other position as the selecting arm 20 is moved between L and H, the circuit is closed thru contacts 26 and 27 and incrementally more or less voltage is available across the terminals of the incandescent lamp 155. The same is true of the operation with the circuit as seen in Figure 4 except that no contacts are closed. The incandescent lamp 115 will be at maximum illumination when the selector arm 20 reaches H whereat the full line voltage is impressed across the lamp 153. It will be apparent that both in Figures 3 and 4 the illuminating intensity of the lamp can be varied up and down between zero and maximum by simply manipulating the control element 24.

The provision of a miniature switch with its inherent click when operated has been found to be even more advantageous in that the operator receives audible assurance that the current is completely off. Without such audible indication, a person might be wont to not quite completely turn the control element to correspond to point L so that even though no visible light is apparent in the extremely low voltage ranges, current might continue to flow thru the bulb 15 and be wasted. There are of course certain applications where no appreciable disadvantage would be experience with the circuit as shown in Figure 4 and for that reason such circuit without a circuit breaker switch is illustrated as a practical embodiment although for most uses it is believed that the circuit of Figure 3 would be preferable.

It has also been found advantageous to mount the autotransformer in the base portion 13 of the lamp body 12. The inherent weight of the voltage dividing unit applied near the base of the lamp proper provides a low center of gravity to the device so that the lamp in its entirety is not easily upset or overturned. This feature is further implemented by the fact that such location of the voltage regulating unit permits the operating element in its most simple mechanical arrangement to be adjacent the lamp base where it is considerably more accessible than up under the shade as is the case in most conventional lamps, and Whereat fumbling, particularly in the dark has caused many a conventional lamp to be damaged or broken by its being upset or knocked over.

It should be understood that the concept of this invention may suggest certain modifications and changes, principally in form, to those skilled in the art, and all such modifications as come within the spirit of this invention are intended to be included within its scope as best defined in the appended claims.

We claim:

1. The combination with a lighting device including a body and an incandescent lamp, of a voltage regulating unit comprising an auto-transformer mounted within said body and in circuit with the incandescent lamp for varying the voltage across the lamp and thereby its illuminating intensity, and control means connected to said auto-transformer extending thru said body and terminating externally thereof for operating the voltage regulating unit Within the body of the device to vary the illuminating intensity of said incandescent lamp.

2. A self-contained lighting unit comprising in combination, a body at least partially hollow, an incandescent lamp, a voltage regulating device comprising an autotransformer operable thru an infinite range of voltages between zero and the line voltage supplying the lamp, and which is subject to substantially no heat losses while in operation thruout said range, in series circuit with said incandescent lamp for varying the voltage across said lamp thru said range to thereby vary its illumination thru a corresponding range, and control means connected to said autotransformer extending thru said body and terminating externally thereof in an operating element for operating said voltage regulating device within said body.

3. A self-contained lighting unit as claimed in claim 2, including a pair of contacts in said series circuit operable to close said circuit and to open said circuit at preselected times.

References Cited in the file of this patent UNITED STATES PATENTS 1,721,176 Campo July 16, 1929 1,772,606 Hopkin, Jr. Aug. 12, 1930 2,014,054 Rood et al Sept. 10, 1935 2,226,025 Stansbury Dec. 24, 1940 2,300,296 Langabeer et al. Oct. 27, 1942 2,426,907 Walsh Sept. 2, 1947 2,511,558 Baker June 13, 1950 

